1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Glue Code for 3-way parallel assembler optimized version of Twofish
4 *
5 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
6 */
7
8#include <crypto/algapi.h>
9#include <crypto/twofish.h>
10#include <linux/crypto.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/types.h>
14
15#include "twofish.h"
16#include "ecb_cbc_helpers.h"
17
18EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
19EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
20
21static int twofish_setkey_skcipher(struct crypto_skcipher *tfm,
22 const u8 *key, unsigned int keylen)
23{
24 return twofish_setkey(tfm: &tfm->base, key, key_len: keylen);
25}
26
27static inline void twofish_enc_blk_3way(const void *ctx, u8 *dst, const u8 *src)
28{
29 __twofish_enc_blk_3way(ctx, dst, src, false);
30}
31
32void twofish_dec_blk_cbc_3way(const void *ctx, u8 *dst, const u8 *src)
33{
34 u8 buf[2][TF_BLOCK_SIZE];
35 const u8 *s = src;
36
37 if (dst == src)
38 s = memcpy(buf, src, sizeof(buf));
39 twofish_dec_blk_3way(ctx, dst, src);
40 crypto_xor(dst: dst + TF_BLOCK_SIZE, src: s, size: sizeof(buf));
41
42}
43EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
44
45static int ecb_encrypt(struct skcipher_request *req)
46{
47 ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
48 ECB_BLOCK(3, twofish_enc_blk_3way);
49 ECB_BLOCK(1, twofish_enc_blk);
50 ECB_WALK_END();
51}
52
53static int ecb_decrypt(struct skcipher_request *req)
54{
55 ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
56 ECB_BLOCK(3, twofish_dec_blk_3way);
57 ECB_BLOCK(1, twofish_dec_blk);
58 ECB_WALK_END();
59}
60
61static int cbc_encrypt(struct skcipher_request *req)
62{
63 CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
64 CBC_ENC_BLOCK(twofish_enc_blk);
65 CBC_WALK_END();
66}
67
68static int cbc_decrypt(struct skcipher_request *req)
69{
70 CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
71 CBC_DEC_BLOCK(3, twofish_dec_blk_cbc_3way);
72 CBC_DEC_BLOCK(1, twofish_dec_blk);
73 CBC_WALK_END();
74}
75
76static struct skcipher_alg tf_skciphers[] = {
77 {
78 .base.cra_name = "ecb(twofish)",
79 .base.cra_driver_name = "ecb-twofish-3way",
80 .base.cra_priority = 300,
81 .base.cra_blocksize = TF_BLOCK_SIZE,
82 .base.cra_ctxsize = sizeof(struct twofish_ctx),
83 .base.cra_module = THIS_MODULE,
84 .min_keysize = TF_MIN_KEY_SIZE,
85 .max_keysize = TF_MAX_KEY_SIZE,
86 .setkey = twofish_setkey_skcipher,
87 .encrypt = ecb_encrypt,
88 .decrypt = ecb_decrypt,
89 }, {
90 .base.cra_name = "cbc(twofish)",
91 .base.cra_driver_name = "cbc-twofish-3way",
92 .base.cra_priority = 300,
93 .base.cra_blocksize = TF_BLOCK_SIZE,
94 .base.cra_ctxsize = sizeof(struct twofish_ctx),
95 .base.cra_module = THIS_MODULE,
96 .min_keysize = TF_MIN_KEY_SIZE,
97 .max_keysize = TF_MAX_KEY_SIZE,
98 .ivsize = TF_BLOCK_SIZE,
99 .setkey = twofish_setkey_skcipher,
100 .encrypt = cbc_encrypt,
101 .decrypt = cbc_decrypt,
102 },
103};
104
105static bool is_blacklisted_cpu(void)
106{
107 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
108 return false;
109
110 if (boot_cpu_data.x86 == 0x06 &&
111 (boot_cpu_data.x86_model == 0x1c ||
112 boot_cpu_data.x86_model == 0x26 ||
113 boot_cpu_data.x86_model == 0x36)) {
114 /*
115 * On Atom, twofish-3way is slower than original assembler
116 * implementation. Twofish-3way trades off some performance in
117 * storing blocks in 64bit registers to allow three blocks to
118 * be processed parallel. Parallel operation then allows gaining
119 * more performance than was trade off, on out-of-order CPUs.
120 * However Atom does not benefit from this parallelism and
121 * should be blacklisted.
122 */
123 return true;
124 }
125
126 if (boot_cpu_data.x86 == 0x0f) {
127 /*
128 * On Pentium 4, twofish-3way is slower than original assembler
129 * implementation because excessive uses of 64bit rotate and
130 * left-shifts (which are really slow on P4) needed to store and
131 * handle 128bit block in two 64bit registers.
132 */
133 return true;
134 }
135
136 return false;
137}
138
139static int force;
140module_param(force, int, 0);
141MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
142
143static int __init twofish_3way_init(void)
144{
145 if (!force && is_blacklisted_cpu()) {
146 printk(KERN_INFO
147 "twofish-x86_64-3way: performance on this CPU "
148 "would be suboptimal: disabling "
149 "twofish-x86_64-3way.\n");
150 return -ENODEV;
151 }
152
153 return crypto_register_skciphers(algs: tf_skciphers,
154 ARRAY_SIZE(tf_skciphers));
155}
156
157static void __exit twofish_3way_fini(void)
158{
159 crypto_unregister_skciphers(algs: tf_skciphers, ARRAY_SIZE(tf_skciphers));
160}
161
162module_init(twofish_3way_init);
163module_exit(twofish_3way_fini);
164
165MODULE_LICENSE("GPL");
166MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
167MODULE_ALIAS_CRYPTO("twofish");
168MODULE_ALIAS_CRYPTO("twofish-asm");
169

source code of linux/arch/x86/crypto/twofish_glue_3way.c